Transcriptional regulation of development and homeostasis in complex eukaryotes, including humans and other mammals, birds, and fish, is controlled by a wide variety of regulatory substances, including steroid and thyroid hormones. These hormones exert potent effects on development and differentiation in phylogenetically diverse organisms and their actions are mediated as a consequence of their interactions with specific, high affinity binding proteins referred to as receptors. See generally, Jensen and DeSombre, A. Rev. Biochem., 41: 203-230 (1972); Gorski and Gannon, A. Rev. Physiol., 38: 425-450 (1976); Yamamoto and Alberts, A. Rev. Biochem., 45: 721-746 (1976a); O'Malley et al., Recent Prog. Horm. Res., 25: 105-160 (1969); Hayward et al., Nucleic Acids Res., 10: 8273-8284 (1982); and Asburner and Berendes in The Genetics and Biology of Drosophila, Ashburner and Wright eds., Academic, London 2: 315-395 (1978).
Receptor proteins, each especially specific for one of the several classes of cognate steroid hormones (i.e., estrogens (estrogen receptor), progestogens (progesterone receptor), glucocorticoids (glucocorticoid receptor), androgens (androgen receptor), aldosterones (mineralocorticoid receptor) or for cognate thyroid hormones (thyroid hormone receptor), are known and distributed in a tissue specific fashion. See Horwitz and McGuire, J. Biol. Chem., 253: 2223-2228 (1978) and Palmiter et al., Cell, 8: 557-572 (1976).
Turning now to the interaction of hormones and receptors, it is known that asteroid or thyroid hormone enters cells by facilitated diffusion and binds to its specific receptor protein. As a result of this alteration, the hormone/receptor complex is capable of binding to certain specific sites on chromatin with high affinity. See Yamamoto and Alberts, Proc. Natl. Acad. Sci. U.S.A., 69: 2105-2109 (1972) and Jensen et al., Proc. Natl. Acad. Sci. U.S.A., 59: 632-638 (1968).
It is also known that many of the primary effects of steroid and thyroid hormones involve increased transcription of a subset of genes in specific cell types. See Peterkofsky and Tomkins, Proc. Natl. Acad. Sci. U.S.A., 60: 222-228 (1968) and McKnight and Palmiter, J. Biol. Chem., 254: 9050-9058 (1968). Moreover, there is evidence that activation of transcription (and, consequently, increased expression) of genes which are responsive to steroid and thyroid hormones (through interaction of chromatin with hormone receptor/hormone complex) is effected through binding of the complex to enhancers associated with the genes (see Khoury and Gruss, Cell, 33: 313-314 (1983)).
In any case, a number of steroid hormone and thyroid hormone responsive transcriptional control units, some of which have been shown to include enhancers, have been identified. These include the mouse mammary tumor virus 5'-long terminal repeat (MTV LTR), responsive to glucocorticoid, aldosterone and androgen hormones; the transcriptional control units for mammalian growth hormone genes, responsive to glucocorticoids, estrogens, and thyroid hormones; the transcriptional control units for mammalian prolactin genes and progesterone receptor genes, responsive to estrogens; the transcriptional control units for avian ovalbumin genes, responsive to progesterones; mammalian metallothionein gene transcriptional control units, responsive to glucocorticoids; and mammalian hepatic alpha.sub.2u -globulin gene transcriptional control units, responsive to androgens, estrogens, thyroid hormones and glucocorticoids. (See the Introduction portion of Experimental Section I of this Specification for references.)
A major obstacle to further understanding and more practical use of the steroid and thyroid hormone receptor has been the lack of availability of the receptor proteins, in sufficient quantity and sufficiently pure form, to allow them to be adequately characterized. The same is true for the DNA gene segments which encode them. Lack of availability of these DNA segments has prevented in vitro manipulation and in vivo expression of the receptor-coding genes, and consequently the knowledge such manipulation and expression will yield.
The present invention is directed to overcoming these problems of short supply of adequately pure receptor material and lack of DNA segments which encode the receptors.
Some of the information disclosed in this specification has been published.
The study disclosed in Experimental Section I has been published as: Hollenberg et al., "Primary Structure and Expression of a Functional Human Glucocorticoid Receptor cDNA", Nature (London), 318: 635-641 (December 1985).
The study disclosed in Experimental Section II has been published as: Giguere et al., "Functional Domains of the Human Glucocorticoid Receptor", Cell, 46: 645-652 (August 1986).
The study disclosed in Experimental Section III has been published as: Weinberger et al., "The c-erb-A Gene Encodes a Thyroid Hormone Receptor" Nature (London) 324: 641-646 (December 1986).
The study disclosed in Experimental Section IV has been published as: Arriza et al., "Cloning of Human Mineralocorticoid Receptor Complementary DNA: Structural and Functional Kinship with the Glucocorticoid Receptor" Science 237: 268-275 (July 1987).
The study disclosed in Experimental Section V is in press as: Giguere et al., "Identification of a New Class of Steroid Hormone Receptors".
The study disclosed in Experimental Section VI is in press as: Glass et al., "A c-erb-A Binding Site in the Rat Growth Hormone Gene Mediates Transactions by Thyroid Hormone".
The study disclosed in Experimental Section VII has been published as: Thompson et al., "Identification of a Novel Thyroid Hormone Receptor Expressed in the Mammalian Central Nervous System", Science, 237: 1610-1614 (September, 1987) .